GPS is not essential to air navigation. It’s nice to have, and there are some approaches that legally require it to be operational in order to fly them (IFR procedures) but aviation has other systems in place to guide aircraft under conditions where visual flight navigation is impossible.
In this case, IMHO, the pilots had become complacent and lax in their navigational rigor because of the fact that GPS makes a lot of the slightly less automated systems unnecessary, and people get used to that workflow.
If the flight crew had been looking at their map and using it to inform them about the mountains in their path, fixing position by the VOR and DME, or even just a stopwatch and compass heading, they would have easily known they needed to be at a higher altitude. Not being precisely sure of their exact position, they should have at least been maintaining the minimum safe altitude for the area they knew they were in.
But unfortunately, people get so used to looking at the shiny screen giving them effortless situational awareness that they forget all of the rules and habits that kept pilots alive for the last century before glass cockpits were a thing, and they forget that mountains are the tigers of the air, always waiting to catch pilots unaware.
This is a useful cautionary tale not only for pilots, but increasingly for humans in general as we become accustomed to a new kind of instrument that allows us to offload a great deal of our cognitive focus to a tool that may sometimes fail.
> GPS is not essential to air navigation. It’s nice to have, and there are some approaches that legally require it to be operational in order to fly them (IFR procedures) but aviation has other systems in place to guide aircraft under conditions where visual flight navigation is impossible.
This has not been the practical reality for many years for IFR flights (arguably not for VFR flight either but some of the good old boys will still argue that you should still be using a map and compass).
In Europe the minimum requirement has been B-RNAV and aircraft are controlled with reference to intersections which have no defined relationships with underlying VORs, and an expectation of being able to navigate direct to one from any arbitrary point in space. Airliners generally get away with this because they have DME-DME disciplined INS. Smaller aircraft, well the backup is vectors from ATC.
This approach is wrong though, as we’re now seeing.
GPS is comically easy to jam or spoof and assuming it will work all the time is just a silly, dangerous assumption.
We just happened to live through a brief period where you could believe that
Yeah, I agree that GPS is too easy to jam and should ideally not be used exclusively but if you are flying anything from a newish C172 to a Cessna Citation (or any other non-long haul business jet) it is the reality.
Annoyingly all of these systems have VOR and DME equipment, it would be trivial to have a back up position to well within en-route navigation accuracy limits and certainly close enough to prevent this kind of accident. But regulation and certification requirements being what they are they are no one does it.
In an ideal world we'd have some kind of INS but the ring laser gyros and accelerometers required are stubbornly expensive.
In this case the call was coming from inside the house. Another win for uncle Sam.
Does Europe not have VORs?
Of course - though many of them have been decommissioned or are in the process. Though recent developments have probably reduced the enthusiasm for removing them so quickly.
However, that doesn't change the fact that the intersection that ATC are flying you towards are actually now defined as coordinates, not radials or distances from nearby VORs.
If an ATC tells you "direct OKSAW" they won't give you a VOR radial to intercept - you are expected to go straight there in a relatively straight line from your current position. There were boxes like the KNS80 that could do VOR-VOR navigation to do this kind of thing but it's not user friendly by modern standards.
When you file your flight plan, there is a box for "equipment". Put "O" there and they will not do that to you anymore. "DO" if you have DME.
This won't work in the UK/Europe. B-RNAV has been a requirement since 11 April 2011 at all ATS controlled routes and levels (previously only above FL95). The only reasonable equipment is a IFR capable panel mounted GPS.
Of course the UK is extra weird because you can fly IFR in class G airspace which is quite extensive outside of terminal areas. More realistically this is VFR in IMC, with the pilot being responsible for his own terrain and traffic separation (somewhere between relying on the "big sky" theory and these days, hopefully, some TCAS system). We even have a special sub-ICAO IR(R) rating which allows a pilot to punch holes in clouds and even to shoot an approach at a airport but not to access the class A TMAs / airways.
Oof...since 2011? Even with everyone knowing that GPS signals are -125 dBm on a good day and anyone can jam them? Jeez! My condolences. At least here stateside one can still fly IFR with a VOR/DME just fine.
This was the partial cause of Air France 447.
Pilots were so used to "the plane won't make a mistake" that they were not aware/not trained properly about things that are nothing to do with the FMS like frozen pitot tubes and also that the autopilot has a number of "modes" which mean you need to go back to basics like altitude, attitude and air speed.
> Pilots were so used to "the plane won't make a mistake" that they were not aware
Of course there have also been crashes where pilots wrongly dismissed sensor data.
In the Kegworth air disaster [1] the pilots had sensor data telling them the left-hand engine was at fault - but a previous model of the plane had a reputation for unreliability in that sensor, and the pilots shut down the right-hand engine on the basis of other evidence.
So we don't want pilots blindly trusting broken sensors - but we also don't want them to dismiss working sensors as broken.
[1] https://www.faa.gov/lessons_learned/transport_airplane/accid...
They didn't know their air speed (because of the pitot tubes being frozen). I think the report says that there was a path to safety if they had kept focused but it wasn't as easy as just flying the plane via 'the basics'.
It was, and one of the pilots was doing the right thing and would have saved the plane no problem if they had been the only one flying the plane. The problem was that the other pilot insisted on doing exactly the wrong thing, didn’t say what he was doing, and the plane didn’t give nearly enough indication that it was receiving contradictory inputs from the two sets of controls.
I don't know what the definitions of "basic" is, but even PPL students are trained to recognize the effects of a frozen pitot tube.
If it’s true that other navigation systems are as safe and capable as GPS, then GPS navigation should be randomly disabled in every aircraft occasionally to ensure that pilots remain fluent in using them.
If it isn’t true, then the military is partially responsible for the crash of this aircraft.
No, pilots should ensure they're current at navigating without GPS because it can fail, just like pilots practice engine failure procedures and every other emergency / non-normal procedure. That doesn't mean it should be "randomly disabled" for the same reason that you don't test software in production or randomly turn off the engine of the plane. Obviously.
We don't know how it failed. Maybe it displayed their lat/long perfectly but at the wrong altitude. We think of failure as obvious, but it is often nearly impossible to tell unless you are looking for it.
Altitude is the least accurate dimension for GPS, and it's also the one dimension that's provided with great accuracy by a really simple mechanical gauge present in every aircraft. There should never be a situation where an incorrect altitude figure from GPS causes a problem.
GPS is a 3D measurement.
Errors can be along any axis, random, infrequent, drifting, and nonobvious.
Depends on the weather. A lot of approaches to airports are GPS only these days. If GPS doesn't work and you are not in VFR weather, you can't fly those approaches. In bad weather you'd be diverting to an airport that still has ILS.
Vectoring by the controller to a visual or ILS approach still works but they'd be juggling a lot of planes. And while lots of the bigger/older airports still have ILS, many VORs and DMEs are being retired and many smaller airports don't have ILS at all.
Denied access to GPS in a large area in bad weather would likely result in lots of flight cancellations and contingency plans getting put in motion to get anything still in the air landed safely. But controllers would get very busy and ILS runways very congested.
Here in Europe, there have been a few cases of GPS denied areas especially closer to Russia. Mostly pilots and controllers at e.g. Helsinki airport are able to deal with this.
lol the very first paragraph of my comment.
But yeah, IFR is getting more dependent on gps approaches…
which is incredibly stupid because it becomes trivial to disrupt air navigation. It’s a bit better with newer chipsets that support GPS, Galileo, GLONASS, and BeiDou… but I’d venture that when the military is jamming I’d does them all. I can buy a jammer that will take out GPS over about a kilometer for less than $1k. They are used all over the place by criminals in many countries, because there often aren’t standardized addresses and if your drug house can’t be located on gps in the favella, you get a lot more warning before a raid. That same transmitter with a directional antenna could knock out a 10 degree sector for 30km.
VMC prevailed at the time of the accident, although it was a dark moonless night. The flight in question only needed to maintain an altitude above the mountains until a visual to the airport was established along with their distance from the runway.
My guess based on the flight path is they had a visual on the airport but were lost and didn’t know where they were. If the gps hadn’t come back on for a minute they probably would have been fine, but it came back on and they fixated on the shiny screen instead of using their navigation skills.
Unless you want trust your life to an instrument, you fly like it might not be trustworthy. Granted, there are many instruments in an airplane we trust our lives to, but they can mostly be cross-referenced against other inputs. The trouble with gps is that it enables procedures that make that essentially impossible, and the major failure mode is not one you can carry an extra for. In aviation, situational awareness is life.
I believe that their are no multi-GNSS receivers certified for aviation, so Galileo, GLONASS and BeiDou are out.
Sure, but every pilot has an iPad, basically, and an iPad with foreflight might have saved their lives. You even get synthetic vision.
Late revision.. either these pilots weren’t using one, or the military was jamming everything. Probably the latter. I can say from my personal experience that it’s really, really easy to get so used to using GPS that you are utterly unprepared to really deal with an alternative. You need to integrate those failure modes into your flight planning, and not just figure you’ll remember everything when your back is against the wall.
To add to this, there's a good lecture called Children of the Magenta Line that discusses automation dependency: https://www.youtube.com/watch?v=5ESJH1NLMLs
Better version: <https://www.youtube.com/watch?v=lIusD6Z-3cU>
Don't worry, our government is doing their level best to make GPS the only option for air navigation. After all, we all know that technology NEVER fails, and the sooner we can turn off all those big bad old ground radars and navigation aids, the sooner we can sell all that real estate and use the money for things that the American public desperately needs, like more corporate bailouts and bathroom security cameras.
That's not accurate. Navigationally critical VORs are continuing to be maintained, they're just turning off the podunk redundant ones.
VOR Candidate Retention List | Federal Aviation Administration https://www.faa.gov/ato/navigation-programs/vor-retention-li...
See specifically the "MON" concept:
> The VOR MON program is designed to enable aircraft, having lost GPS service, to revert to conventional navigation procedures. This will allow users to continue through the outage area using VOR station-to-station navigation or to proceed to a MON airport where an Instrument Landing System (ILS), Localizer (LOC) or VOR approach procedure can be flown without the necessity of GPS, Distance Measuring Equipment (DME), Automatic Direction Finder (ADF), or surveillance. Any airport with a suitable instrument approach may be used for landing, but the VOR MON assures that at least one airport will be within 100 Nautical Miles (NM).
* https://www.faa.gov/about/office_org/headquarters_offices/at...
2011:
* https://www.federalregister.gov/documents/2011/12/15/2011-31...
They are continuing to be maintained only because the FAA fought very hard for that ability. The rest of the government does not understand (or care) why the FAA wants to keep "obsolete" systems, and the FAA is subject to their legislative whims.
Everyone knows what the police need to catch more criminals is a comprehensive network of underseat security cameras. I’m sure they would never misuse that kind of access.
They’re going to eliminate windows?
The weather already does that on a regular basis... though they are doing their best to make the weather, on average (i.e. what you might call a climate), worse.
Worse is a value judgement and, in context, the value would be "ability to fly by sight".
Is climate change going to make it more difficult to see outside?
The value here is pretty simple, the frequency at which windows are rendered useless due to weather.
Yes, the change we are undergoing and that the current administration seems to be doing their best to accelerate includes an increase in heavy precipitation across north america.
That's good news for the data centers.
More destructive weather events are good for expensive pieces of infrastructure? Higher temperatures are good for things that struggle to cool themselves? I don't see it.
I thought they were shutting down VORs to save money and relying more and more on RNAV (i.e. GPS) approaches.